Demon Carb: New Street Demon 625-CFM

This new Street Demon cabureretor is the best one yet

Despite the fact that we live in the high-tech world of the 21st century, there’s still room for a new idea or two, even in the world of carburetors. And so it is that Street Demon Carburetion, which is back in business, thank you, has come out with a brand-new carburetor, appropriately named the new Street Demon: Demon Carb. Appearances tell us it’s clearly not a fluffed-up version of the old Demon but a new casting. It’s a bit of a hybrid that takes proven, fuel-mixing ideas from the old Carter air-valve secondary (AVS) carbs and the Thermo-Quad, combining them with a couple of new wrinkles to improve part-throttle driveability. Speaking of which, we bolted this carb (PN 1901) to our ’65 El Camino equipped with a 290hp Chevrolet Performance crate engine that is modified with a Comp Cams Thumpr camshaft. The El Camino sports a four-speed and 3.08:1 gears, which makes this a serious low-speed carb-signal test and a major party foul with its combination of a big overlap camshaft and tall rear gears. Every previous carb we’ve tried stumbled badly off idle just as the clutch engaged. This carb also experiences a lean stumble out of the box, though it recovers much more quickly than the other carburetors, and we might be able to remedy the issue with accelerator-pump-squirter or power-valve-spring mods. Speaking of part-throttle tuning, this carb should be a little easier in that regard, as it allows changing the primary metering rods and enrichment springs (which operate much like a power valve) without having to disassemble the carb. This makes the Street Demon: Demon carb one of the easier carburetors to tune for better street manners. Perhaps best of all, the basic 625 Street Demon is priced less than $350. So there are several reasons to like this new Street Demon.